Methods are known for managing an electromechanical brake actuator that comprises an electric motor adapted to move a pusher facing a stack of disks in order to apply a braking force selectively to the stack of disks.
As an example of such a brake, FIG. 1 is a section view of an electromechanical brake 3 for an aircraft that is mounted on an axle 2 of an undercarriage of the aircraft and that carries a wheel rim 1 (for receiving a tire that is not shown). Such a brake 3 comprises a torsion tube 4 secured to the axle 2 and a stack of disks 5 extending between the torsion tube 4 and the wheel rim 1. The stack of disks 5 comprises first disks (referred to as “rotor” disks) constrained to rotate with the rim 1, and second disks (referred to as “stator” disks) disposed in alternation with the first disk and constrained in rotation with the torsion tube 4, such that they do not rotate with the rim. Facing the stack of disks there is a ring 6 secured to the torsion tube 4 and carrying electromechanical actuators 7, each comprising an electric motor (not shown) adapted to move a pusher 8 facing the stack of disks 5 in order to apply a braking force thereto in selective manner.
As shown in FIG. 2, which is a graph plotting the operating range or domain of the electric motor of one of the actuators 7 in the current/speed plane, said operating domain D includes in conventional manner a boundary defined firstly by a first straight line 10 (sloping downwards) at a gradient that depends on the characteristics and the dimensions of the motor, and at a height that is determined by the power supply voltage selected for the motor, and secondly a second straight line 11 (a vertical line) defined by a maximum current that should not be exceeded while the motor is in operation, in particular for the purpose of protecting the power components associated with the motor.
Typical operating points for brake actuators lie firstly in the vicinity of the intersection of the speed axis and the first straight line 10, such as the operating point 12, corresponding to a stage during which the pusher 8 is approaching the disks 5 at high speed, and secondly in the vicinity of the intersection between the current axis and the second straight line 11, such as operating point 13, corresponding to a state in which the pusher 8 is applying a force against the disks 5.
In general, on aircraft, the power available is limited and it is important to ensure that the actuators cannot draw power greater than the maximum authorized power pmax in order to avoid triggering the aircraft's electrical protection devices of the circuit breaker type.
This constraint thus leads to an operating domain D being defined which, in the current/speed plane, extends entirely beneath the constant power curve 14 corresponding to the maximum authorized power Pmax.
This limitation leads to the performance of the actuator being under-utilized.